Effects of neutron-nuclei interactions in the neutron
star crust

Rishi SharmaT2

At densities greater than neutron drip, the neutron
star crust features a plasma of neutron-rich nuclei and electrons, bathed in a gas of
unbound neutrons. If the two systems are treated separately, as is typically done, one
concludes that the nuclei form a lattice and the neutrons pair up and form a superfluid.
The low energy excitations of such a system will feature lattice vibrations and phase
fluctuations of the superfluid condensate. Interactions between the unbound neutrons and
nuclei affect the properties of the two modes (for example, propogation speed) and
introduce a mixing betwen the two. These effects play an important role in determining
the transport and structural properties of the inner crust of a neutron star.